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Biology subjects

Min, L.

Publications and source records attributed to Min, L..

17 recordsLinked to original sources

Human and Mouse Models of the Bipolar Disorder-Associated ANK3 p.W1989R Variant Display Altered Somatostatin Interneuron Connectivity and Function

Bipolar disorder (BD) is a debilitating neuropsychiatric disorder characterized by recurrent mood perturbations, cognitive and functional impairment, and increased risk of suicide. Genome-wide association studies (GWAS) have repeatedly identified the gene ANK3, which encodes the neuronal scaffolding protein ankyrin-G, as a risk locus for BD. Ankyrin-G interacts directly with the GABAA receptor-associated protein (GABARAP) to stabilize inhibitory synapses, providing a potential mechanistic link between ANK3 variation and GABAergic dysfunction observed in BD. Previously, we identified an ANK3 p.W1989R variant in a family with BD and demonstrated that this variant abolishes the ankyrin-G/GABARAP interaction, resulting in inhibitory signaling deficits in mice. Here, we investigated the effects of this variant in human induced pluripotent stem cell (hiPSC)-derived neurons generated from an affected individual heterozygous for the ANK3 p.W1989R variant. CRISPR correction of the variant increased inhibitory synapse density on both glutamatergic and GABAergic patient-derived neurons. Integrated spatial transcriptomics and calcium imaging identified cell-type-dependent changes in gene expression and calcium dynamics. ANK3 p.W1989R somatostatin (SST) positive interneurons displayed altered calcium dynamics and reduced SST expression. To determine whether the variant impacts SST interneuron-mediated inhibition of cortical circuits, we selectively stimulated prefrontal cortical SST interneurons in heterozygous Ank3 p.W1989R mice and recorded optically evoked inhibitory postsynaptic currents (oIPSCs) from cortical pyramidal neurons. SST interneuron-mediated oIPSC peak amplitude, charge transfer, and decay times were reduced in variant mice, without a significant change in the paired-pulse ratio. These findings, using complementary human and mouse models, identify novel roles for ankyrin-G in SST interneuron-mediated inhibitory signaling and demonstrate that altered inhibitory connectivity and SST interneuron function are associated with ANK3 p.W1989R. This work provides mechanistic insight into how disrupted ankyrin-G-dependent synaptic function may contribute to inhibitory signaling deficits relevant to BD.

neuroscience↗

HnRNPAB-targeted antisense oligonucleotides ameliorate tau pathology and cognitive deficits by modulating Alzheimers disease-associated alternative splicing

Aberrant alternative splicing alters multiple disease-associated splicing events, including MAPT exon 10 inclusion linked to tau pathology, and thereby impacts Alzheimers disease (AD) progression. Heterogeneous nuclear ribonucleoprotein AB (hnRNPAB) functions as a splicing regulator, yet its roles in AD remain poorly defined. Here, we identified AB332, the full-length isoform of hnRNPAB, as a novel repressor of MAPT exon 10 inclusion. AB332 binds a conserved AAUAU motif and recruits RBMX and RBMXL1 through its RRM and glycine-rich domains to assemble a complex. Beyond MAPT, AB332 modulates a network of splicing events in multiple AD-associated genes, including STAG2, ApoER2, MCL-1, PICALM, and zDHHC7. Importantly, the exon 7-skipping isoform AB285 lacks these activities. Transcriptomic analysis of post-mortem brain tissues from AD patients revealed reduced expression of hnRNPAB, while selective downregulation of AB332 was confirmed in the hippocampus of 3xTg AD mice. We performed a systematic antisense oligonucleotide-tiling screen targeting hnRNPAB exon 7 and its flanking intronic regions, identifying ASO30 that specifically upregulated AB332 expression. In 3xTg AD mice, ASO30 restored hippocampal AB332 levels, reduced pathological tau phosphorylation, and rescued cognitive deficits. These findings define a molecular mechanism by which AB332 regulates AD-associated splicing events, thereby providing a therapeutic strategy targeting hnRNPAB for AD. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=79 SRC="FIGDIR/small/736008v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@621096org.highwire.dtl.DTLVardef@2f01b1org.highwire.dtl.DTLVardef@182e6forg.highwire.dtl.DTLVardef@190afd3_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

Universal physical principles govern the deterministic genesis of protein structure

Protein structure is usually treated as the endpoint of sequence by most AI models, yet its true biological emergence is a process of ordered change, whose logic remains hidden in opaque black box. ProtGenesis creates a bidirectional mirror world: it maps amino acid assembly, elongation and mutation in biological space into quantitative trajectories and ensembles in protein language model representation space, then translates spatial geometry into testable biophysical hypotheses. Across peptides, reporter proteins and protein families, three universal general principles emerged: hierarchical directional assembly (Principle I), quantitative and reproducible structural-emergence trajectories (Principle II) and discrete topological transitions (Principle III) from short- to long-range order. Three novel metrics of spatial features [D,{rho} ,{delta} ], complemented by squared Gaussian Wasserstein-2 measures, located structural anchors, sensitive regions and state transitions, enabling split-protein engineering and programmable protein design. ProtGenesis makes latent representations mechanistically interpretable, offering AI a route to discovering, rather than merely predicting, scientific principles. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=173 HEIGHT=200 SRC="FIGDIR/small/706798v2_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@18f690org.highwire.dtl.DTLVardef@e36903org.highwire.dtl.DTLVardef@35f15org.highwire.dtl.DTLVardef@1577b81_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

A neuron type-specific microexon in Ank3/ankyrin-G modulates calcium activity and neuronal excitability

Recent studies have revealed many alternative exons differentially spliced across diverse neuron types in the mammalian brain, but their links to neuronal physiology remain unclear. Here we characterize a deeply conserved microexon E35a in Ank3 encoding ankyrin-G (AnkG), a multifaceted adaptor protein best known as a master organizer of the axon initial segment (AIS) and as a leading genetic risk factor for bipolar disorder. E35a is predominantly skipped in cortical glutamatergic neurons but included in cortical GABAergic neurons and cerebellar neurons, which is dictated by multiple neuronal splicing factors. In E35a-deletion mice we generated, interneurons show increased excitability and somatic Ca2+ activity, without disruption in AIS. Biochemical analyses suggest that E35a inclusion facilitates AnkG interaction with a protein complex involving inositol trisphosphate receptors (InsP3Rs) important for intracellular Ca2+ signaling. Alternative splicing therefore allows AnkG to modulate neuron type-specific excitability in addition to its ubiquitous pan-neuronal role in organizing the AIS.

neuroscience↗

Structural Basis for Cas9-Directed Spacer Acquisition in Type II-A CRISPR-Cas Systems

CRISPR-Cas systems confer prokaryotic adaptive immunity by integrating foreign DNA (prespacers) into host arrays. Type II-A systems employ Cas9 for protospacer adjacent motif (PAM) recognition and coordinate with Csn2 and the Cas1-Cas2 integrase during spacer acquisition, yet their structural basis remains unresolved. Here, we report cryo-EM structures of the Enterococcus faecalis Cas9-Csn2-Cas1-Cas2 supercomplex in apo and DNA-bound states. The apo-state structure (Cas92-Csn28-Cas18-Cas24) adopts a resting conformation, with Cas9 locked in a nuclease-inactive state and Cas1-Cas2 sterically blocked from prespacer loading. Upon DNA engagement, Cas9 undergoes a conformational transition, forming a prespacer catching complex that threads the DNA through Csn2s central channel. This architecture enables Cas9 to interrogate the PAM sequence while sliding along the DNA, with Cas9 and Csn2 jointly define a 30-bp DNA segment which matches the prespacer length. Subsequent dissociation of Cas9 triggers a structural reconfiguration of the Csn2-Cas1-Cas2 assembly. The PAM-proximal DNA becomes accessible, and Cas1-Cas2 relocates to bind to the exposed DNA, enabling further prespacer processing and directional integration. These findings reveal how Cas9 collaborates with Csn2 and Cas1-Cas2 to couple PAM recognition with prespacer selection, resolving the dynamic structural transitions that ensure fidelity during type II-A CRISPR adaptation.

molecular biology↗

MiRNA Locker: A Modularized DNA Assembly As miRNA Inhibitors

MicroRNAs (miRNAs) are vital post-transcriptional regulators that govern key cellular processes such as proliferation, migration, and apoptosis. Current loss-of-function approaches, including chemically modified antisense oligonucleotides (ASOs), face significant challenges, including high costs, limited scalability, and off-target effects. To overcome these limitations, we developed "miRNA Locker", a novel miRNA inhibition platform created using the Overlapped Oligo Assembly (OOA) method. This innovative platform constructs highly stable dumbbell-shaped single-stranded DNA structures, offering improved target specificity, scalability, and cost-effectiveness. Using miR-214 as a proof-of-concept target, we demonstrated that miRNA Lockers effectively bind Argonaute-miRNA complexes, reduce miRNA levels, and induce downstream changes in gene expression and cellular phenotypes, surpassing the performance of commercial antagomirs. Furthermore, applying miRNA Lockers to miR-654 validated the regulatory role of miR-654 in modulating RNF8 expression and promoting epithelial-mesenchymal transition (EMT) in lung cancer cells. Our results highlight the potential of miRNA Lockers as a versatile tool for studying miRNA function and advancing miRNA-based therapies. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=114 SRC="FIGDIR/small/632138v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@c6ac1eorg.highwire.dtl.DTLVardef@14e2698org.highwire.dtl.DTLVardef@1c7d84aorg.highwire.dtl.DTLVardef@148f9c1_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

Exploring the Hypothetical Role of Bacteroides Species in Depression Progression: Insights from Metagenomic Analysis

Depression, a psychiatric disorder with significant morbidity and mortality, has a complex etiology. Recent advances in microbiome research have highlighted the potential role of gut microbiota in depression pathogenesis. This study utilized shotgun metagenomic sequencing to compare the fecal microbiota of 28 depression patients and 26 healthy individuals. Significant differences in gut microbiota composition were observed between the two groups. We generated 350 non-redundant high-quality metagenome-assembled Genomes (MAGs) by binning and conducted comparisons between the depression and control groups. Notably, we found that the MAGs enriched in people with depression mostly belonged to Bactendicating a close link between Bacteroides abundance and the development of depression, suggesting that Bacteroides might be a potential culprit for deroides, ipression. In the depression group, we found that the module of nitric oxide synthesis was remarkably enriched, and all Bacteroides MAGs were annotated to nitric oxide synthase, suggesting that increased levels of Bacteroides may contribute to elevated nitric oxide synthesis. Specifically, the mean relative abundance about the genomes of Bacteroides xylanisolvens, Bacteroides caccae, Bacteroides fragilis, Bacteroides stercoris and Bacteroides ovatus showed strong discriminatory power in distinguishing depressed patients from healthy individuals (AUC=0.834). This research shed light on the potential role of gut microbiota in depression and highlights specific metabolic pathways and microbial markers for further investigation. ImprotanceThis research highlighted significant differences in the composition and function of gut microbiota between individuals with depression and healthy individuals, particularly the enrichment of Bacteroides MAGs in depression patients. The upregulation of the nitric oxide synthesis pathway associated with these MAGs belong to Bacteroides in the gut of depression patients had also been observed. The mean relative abundance of a specific set of Bacteroides MAGs had been identified, which could accurately classify individuals with depression from healthy individuals (AUC=0.834). Our results suggest the importance of exploring microbial markers as potential diagnostic and therapeutic targets in managing depression.

genomics↗

Why the adventitious roots of poplar are so colorful: RNAseq and metabolomic analysis reveal flavonols, flavones, and anthocyanins accumulation in canker pathogens-induced adventitious roots in poplar

Recently, we observed a novel allometry on poplar stems, with copious colorful adventitious roots (ARs) induced by fungal canker pathogens. Here, we reveal chemical, physiological, and molecular mechanisms of AR coloration in a poplar-pathogen (Valsa sordida/Botrosphaeria dothidea) interaction system using our phloem girdling-inoculation system. Light-induced coloration in ARs: red/rosy under sunlight and milky white under shading. Chemical and metabolomic analyses indicated that numerous (93 in all 110) and high relative intensities/contents of flavonoids metabolites (mainly including flavonols, flavones, and anthocyanins class) accumulate in red ARs, some flavones and anthocyanins metabolites all contribute to the color of poplar ARs, and cyanidin-3-O-glucoside is the most abundant colorant. Integrated analysis of metabolomic and transcriptomic analysis suggested that sunlight exposure redirected metabolomic flux from the flavonoid biosynthesis pathway to the flavonols and flavones branch pathways, induced by the upregulation of FLS (flavonol synthase/flavanone 3-hydroxylase) and other structural genes. The anthocyanins metabolomic analysis and the downregulation of the ANS (anthocyanin synthase) gene illustrated a retard of metabolomic flux from leucoanthocyanidins to anthocyanidins; meanwhile, metabolomic results and the upregulation of gene BZ1 (Bronze 1, anthocyanin 3-O-glucosyltransferase) illustrated that sunlight triggered a rapid biosynthesis of anthocyanin metabolites in poplar ARs, which based on the substrate level of anthocyanidins. Transcriptomic and RT-qPCR analyses showed that transcriptional factor MYB113, HY5 (ELONGATED HYPOCOTYL5), and COP1 (Ring-finger protein CONSTITUTIVE PHOTOMORPHOGENIC1) genes positively regulate the expression of the flavonoid/anthocyanin biosynthesis structural genes (such as genes encoding BZ1, FLS, LAR, etc.) in both sunlight-exposed red ARs and white ARs after light exposure, suggesting sunlight induces anthocyanins biosynthesis through the interaction between "MBW" complex and COP1-HY5 module. Moreover, results also showed that 1 SPL gene (squamosa promoter-binding-like protein gene, target of miR156), one component of miR156-SPL module, downregulated in sunlight-exposed poplar ARs, implying the biosynthesis flavonoid/anthocyanin be regulated at the posttranscriptional level. Additionally, this study provides a potential AR experimental system for research on flavonoid/anthocyanin biosynthesis in tree species.

plant biology↗

Effects of chronic lithium treatment on neuronal excitability and GABAergic transmission in an Ank3 mutant mouse model

Bipolar disorder (BD) is a prevalent psychiatric condition characterized by mood dysregulation, psychosocial impairment, and an increased risk of suicide. The gene ANK3 has been identified as a risk locus for BD through multiple genome-wide association studies (GWAS). However, the mechanisms by which ANK3 variants influence BD pathophysiology and treatment response remain unclear. ANK3 encodes ankyrin-G, a protein that organizes the axon initial segment (AIS) and nodes of Ranvier by scaffolding ion channels and cell adhesion molecules to the cytoskeleton. Recent studies show that ankyrin-G interacts with the GABAA receptor-associated protein (GABARAP) to stabilize inhibitory synapses, potentially linking ANK3 variants to inhibitory (GABAergic) signaling deficits associated with BD. We previously demonstrated that the BD-associated variant, ANK3 p.W1989R, disrupts the ankyrin-G/ GABARAP interaction, resulting in inhibitory deficits and cortical pyramidal neuron hyperexcitability in mice. In this study, we investigate how lithium, a common BD therapeutic, modulates neuronal excitability in this model. Our findings show that chronic lithium treatment selectively enhances presynaptic GABAergic neurotransmission, reduces neuronal hyperexcitability, and partially rescues AIS length, without altering the density of GABAergic synapses. We also show that the selective glycogen synthase kinase-3 beta (GSK-3{beta}) inhibitor Tideglusib recapitulates the enhancement of presynaptic GABAergic signaling. These findings shed new light on how ANK3 variants may contribute to inhibitory deficits in BD and demonstrate that lithium treatment is able to restore these deficits, likely through GSK-3{beta} inhibition. Furthermore, these findings highlight GSK-3{beta} inhibition as a promising therapeutic strategy for treating BD and other neurological disorders affected by GABAergic dysfunction.

neuroscience↗

Circulating Small Extracellular Vesicle RNA Profiling for the Detection of T1a stage Colorectal Cancer and Precancerous Advanced Adenoma

It takes more than twenty years for normal colorectal mucosa to develop into metastatic carcinoma. The long time window provides a golden opportunity for early detection to terminate the malignant progression. Here we aim to enable liquid biopsy of T1a stage colorectal cancer (CRC) and precancerous advanced adenoma (AA) by profiling circulating small extracellular vesicle (sEV)-derived RNAs. We exhibited a full RNA landscape for the circulating sEVs isolated from 60 participants. A total of 58,333 annotated RNAs were detected from plasma sEVs, among which 1,615 and 888 sEV-RNAs were found differentially expressed in plasma from T1a stage CRC and AA compared to normal controls (NC). Then we further categorized these sEV-RNAs into 6 modules by a weighted gene coexpression network analysis and constructed a 60-gene t-SNE model consisting of the top 10 RNAs of each module that could well distinguish T1a stage CRC/AA from NC samples. Some sEV-RNAs were also identified as indicators of specific endoscopic and morphological features of different colorectal lesions. The top-ranked biomarkers were further verified by RT-qPCR, proving that these candidate sEV-RNAs successfully identified T1a stage CRC/AA from NC in another cohort of 124 participants. Finally, we adopted different algorithms to improve the performance of RT-qPCR-based models and successfully constructed an optimized classifier with 79.3% specificity and 99.0% sensitivity. In conclusion, circulating sEVs of T1a stage CRC and AA patients have distinct RNA profiles, which successfully enable the detection of both T1a stage CRC and AA via liquid biopsy.

bioinformatics↗

Physical and functional convergence of the autism risk genes Scn2a and Ank2 in neocortical pyramidal cell dendrites

Dysfunction in sodium channels and their ankyrin scaffolding partners have both been implicated in neurodevelopmental disorders, including autism spectrum disorder (ASD). In particular, the genes SCN2A, which encodes the sodium channel NaV1.2, and ANK2, which encodes ankyrin-B, have strong ASD association. Recent studies indicate that ASD-associated haploinsufficiency in Scn2a impairs dendritic excitability and synaptic function in neocortical pyramidal cells, but how NaV1.2 is anchored within dendritic regions is unknown. Here, we show that ankyrin-B is essential for scaffolding NaV1.2 to the dendritic membrane of mouse neocortical neurons, and that haploinsufficiency of Ank2 phenocopies intrinsic dendritic excitability and synaptic deficits observed in Scn2a+/- conditions. Thus, these results establish a direct, convergent link between two major ASD risk genes and reinforce an emerging framework suggesting that neocortical pyramidal cell dendritic dysfunction can be etiological to neurodevelopmental disorder pathophysiology.

neuroscience↗

Declining population sizes and loss of genetic diversity in commercial fishes: a simple method for a first diagnostic

Exploited fish species may have or are experiencing declines in population sizes coupled with a decrease in genetic diversity. This can lead to the loss of adaptive potential to face current and future environmental changes. However, little is known about this subject while research on it is urgently needed. Thus, this study aims to answer a simple, even naive question, given the complexity of the subject: Could we use a simple method to obtain information on the loss of genetic diversity in exploited fish species? We investigated the use of the levels of genetic diversity in the widely used genetic marker Cytochrome C Oxidase subunit I (COI) mitochondrial gene. Estimates of genetic diversity in COI were obtained for populations of seven fish species with different commercial importance from the East China Sea. These estimates were contrasted against a large dataset of fish species distributed worldwide (N=1426), a dataset of East-Asian fish species (N=118), two farmed species with expected low genetic diversity, and four long-term managed species from the Mediterranean Sea. We found that estimates of genetic diversity in COI match the expectations from theoretical predictions, known population declines, and fishing pressures. Thus, the answer to our question is affirmative and we conclude that estimates of genetic diversity in COI provide an effective first diagnostic of the conservation status of exploited fish species. This simple and cost-effective tool can help prioritize research, management, and conservation on species with suspected loss of genetic diversity potentially eroding their adaptive potential to global change.

ecology↗

Fast anther dehiscence state recognition system establishing by deep learning to screen heat tolerant cotton

Cotton is one of the most economically important crops in the world. The fertility of male reproductive organs is a key determinant of cotton yield. The anther dehiscence or indehiscence directly determine the probability of fertilization in cotton. Thus, the rapid and accurate identification of cotton anther dehiscence status is important for judging anther growth status and promoting genetic breeding research. The development of computer vision technology and the advent of big data have prompted the application of deep learning techniques to agricultural phenotype research. Therefore, two deep learning models (Faster R-CNN and YOLOv5) were proposed to detect the number and dehiscence status of anthers. The single-stage model based on YOLOv5 has higher recognition efficiency and the ability to deploy to the mobile end. Breeding researchers can apply this model to terminals to achieve a more intuitive understanding of cotton anther dehiscence status. Moreover, three improvement strategies of Faster R-CNN model were proposed, the improved model has higher detection accuracy than YOLOv5 model. In addition, the percentage of dehiscent anther of randomly selected 30 cotton varieties were observed from cotton population under normal temperature and high temperature (HT) conditions through the integrated Faster R-CNN model and manual observation. The result showed HT varying decreased the percentage of dehiscent anther in different cotton lines, consistent with the manual method. Thus, this system can help us to rapid and accurate identification of HT-tolerant cotton. One sentence summaryThe deep learning technique was applied to identify the anther dehiscence state for the first time to quickly screen heat tolerant cotton varieties and help to explore key genetic improvement genes.

bioengineering↗

Clonally expanded CD38hi cytotoxic CD8 T cells define the T cell infiltrate in checkpoint inhibitor-associated arthritis

Immune checkpoint inhibitor (ICI) therapies that promote T cell activation have improved outcomes for advanced malignancies yet also elicit harmful autoimmune reactions. The T cell mechanisms mediating these iatrogenic autoimmune events remain unclear. Here we assayed T cells from joints of patients affected by ICI-induced inflammatory arthritis (ICI-arthritis), which can present clinically indistinguishable from rheumatoid arthritis (RA). Compared to the autoimmune arthritides RA and psoriatic arthritis (PsA), ICI-arthritis joints contained an expanded CD38hi CD127- CD8+ T cell subset that displays cytotoxic, effector, and interferon (IFN) response signatures. The abundance of CD38hi CD8 T cells in ICI-arthritis resulted from a limited number of clones that could be found proliferating in the joint. Exposure of synovial T cells to Type I IFN, more so than IFN-{gamma}, induces the CD38hi cytotoxic phenotype. Relative to other CD8+ T cell subsets in the joints, the CD38hi population is distinct from a dysfunctional population and clonally most related to TCF7+ memory populations. Examination of synovial tissue from bilateral knee arthroplasty demonstrated considerable sharing of TCR clonotypes in the CD38hi CD8 T cell fraction from both knees. These results define a distinct CD8 T cell subset that may be directly activated by ICI therapy and mediate a tissue-specific autoimmune cellular reaction in patient joints.

immunology↗

Integrated bioinformatic analysis of miR-654-5p target genes and experimental validation of functional analyses

The pivotal roles of miRNAs in carcinogenesis, metastasis, and prognosis have been demonstrated recently in various cancers. This study intended to investigate the specific roles of hsa-miR-654-5p in lung cancer, which was poorly discussed. A series of closed-loop bioinformatic functional analyses were integrated with in vitro experimental validation to explore the overall biological functions and pan-cancer regulation pattern of miR-654-5p. We found that miR-654-5p abundance was significantly elevated in LUAD tissues and correlated with patients survival. 275 potential targets of miR-654-5p were then identified and the miR-654-5p-RNF8 regulation axis was validated in vitro as a proof of concept. Furthermore, we revealed the tumor-suppressing roles of miR-654-5p and demonstrated that miR-654-5p inhibited lung cancer cell epithelial-mesenchymal transition (EMT) process, cell proliferation, and migration using target-based, abundance-based and ssGSEA-based bioinformatic methods and in vitro validation. Following the construction of a protein-protein interaction network, 11 highly interconnected hub genes were identified and a five genes risk scoring model was developed to assess their potential prognostic ability. Our study will not only provide a basic miRNA-mRNA-phenotypes reference map for understanding the function of miR-654-5p in different cancers but also reveal the tumor-suppressing roles and prognostic values of miR-654-5p in lung cancer. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=199 HEIGHT=200 SRC="FIGDIR/small/423719v2_ufig1.gif" ALT="Figure 1"> View larger version (55K): org.highwire.dtl.DTLVardef@15da4caorg.highwire.dtl.DTLVardef@edfbb6org.highwire.dtl.DTLVardef@289028org.highwire.dtl.DTLVardef@1105a2e_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

Predator: A novel method for targeted protein degradation

Protein expression and degradation are fundamental to cell function and physiological status of organisms. Interfering with protein expression not only provides powerful strategies to analyze the function of proteins but also inspires effective treatment methods for diseases caused by protein dysfunction. Recently, harnessing the power of the ubiquitin-proteasome system for targeted protein degradation (TPD) has become the focus of researches. Over the past two decades, TPD technologies, such as E3 ligase modification, PROTACs, and the Trim-Away method, have successfully re-oriented the ubiquitin-proteasome pathway and thus degraded many pathogenic proteins and even "undruggable" targets. However, A low-cost, convenient, and modularized TPD method is currently not available. Herein, we proposed a synthetic biology TPD method, termed Predator, by integrating the classic function of E3 ligase Trim21 and the expression of a bifunctional fusion protein that links Trim21 and the target protein, which leads to the formation of a ternary complex inside mammalian cells and therefore induce the ubiquitination and subsequent proteasome-dependent degradation of the target protein. We first proved this concept by using nanobody and scFv as the targeting module for the Predator system to degrade free GFP and membrane protein ErbB3, respectively. Then, we give an example of how the engineered Predator system can be developed towards biomedical solutions in the context of diabetes mellitus. Ligands-receptor interaction and adenovirus-mediated gene delivery were introduced to the Predator system, and we found this bifunctional fusion protein, in which glucagon was selected to function as the targeting module, downregulated the endogenous glucagon receptor (GCGR) and attenuated glucagon-stimulated glucose production in primary hepatocytes. Although preliminarily, our results showed that this Predator system is a highly modularized and convenient TPD method with good potential for both fundamental researches and clinical usage. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=160 HEIGHT=200 SRC="FIGDIR/small/231787v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@21e152org.highwire.dtl.DTLVardef@4ff069org.highwire.dtl.DTLVardef@309d74org.highwire.dtl.DTLVardef@1b1653d_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

Phage-Antibiotic Synergy Is Driven By A Unique Combination Of Antibacterial Mechanism Of Action And Stoichiometry

The continued rise in antibiotic resistance is precipitating a medical crisis. Bacteriophage (phage) has been hailed as one possible therapeutic option to augment the efficacy of antibiotics. However, only a handful of studies have addressed the synergistic relationship between phage and antibiotics. Here, we report a comprehensive analysis of phage-antibiotic interaction that evaluates synergism, additivism, and antagonism for all classes of antibiotics across clinically achievable stoichiometries. We combined an optically-based real-time microtiter plate readout with a matrix-like heatmap of treatment potencies to measure phage and antibiotic synergy (PAS), a process we term synography. Phage-antibiotic synography was performed against a pandemic drug-resistant clonal group of E. coli (ExPEC) with antibiotic levels blanketing the minimum inhibitor concentration (MIC) across seven orders of viral titers. Our results suggest that, under certain conditions, phages provide an adjuvating effect by lowering the MIC for drug-resistant strains. Furthermore, synergistic and antagonistic interactions are highly dependent on the mechanism of bacterial inhibition by the class of antibiotic paired to the phage, and when synergism is observed, it suppresses the emergence of resistant cells. Host conditions that simulate the infection environment, including serum and urine, suppress PAS in a bacterial growth-dependent manner. Lastly, phage burst size seems to be a significant driver of synergism. Collectively, this data suggests lytic phages can resuscitate an ineffective antibiotic for previously resistant bacteria, while also synergize with antibiotics in a class-dependent manner, processes that may be dampened by lower bacterial growth rates found in host environments. Significance StatementBacteriophage (phage) therapy is a promising approach to combat the rise of multi-drug resistant bacteria. Currently, the preferred clinical modality is to pair phage with an antibiotic, a practice thought to improve efficacy. However, antagonism between phage and antibiotics has been reported, the choice of phage and antibiotic is not often empirically determined, and the effect of the host factors on the effectiveness is unknown. Here, we interrogate phage-antibiotic interactions across antibiotics with different mechanisms of action. Our results suggest that phage can lower the working MIC for bacterial strains already resistant to the antibiotic, is dependent on the antibiotic class and stoichiometry of the pairing, and is dramatically influenced by the host microenvironment.

microbiology↗